Textural interest can be created by mixing flowers of different kinds and at varying stages of development. The natural texture of flowers, such as the feathery edges of Fern Fiddleheads, velvety smooth surface of Rose petals, and the frothy texture of Hydrangeas, can establish a textural dynamic that creates depth and realism with permanent flowers.
Using multiple kinds of foliage with ribbon and florals can also create a pleasing combination of texture and color.
For example, "Likeside" (left) with its wood texture of the grapevine, feathery Honey Locust leaves, spiky Sweetgum balls, hair-like centers of the Cone Flowers, and velvety smooth ribbon helps to make this wreath not just full but with a lot of texture.
Additionally, using an odd number of stems in an arrangement also creates an interesting shift in focus. Try mixing leaves of different shapes in different shades of green in one arrangement for a more subtle effect.